Add a missing #include.

diff --git a/futatabi/db.cpp b/futatabi/db.cpp
index 13e3f6ee7174dc105df1de4136dff33c905e5bd0..fb6694be3a2f2c729edefedcd3d923a9a4ca2209 100644 (file)
--- a/futatabi/db.cpp
+++ b/futatabi/db.cpp
@@ -3,6 +3,7 @@
 #include "frame.pb.h"
 
 #include <string>
+#include <unordered_set>
 
 using namespace std;